Green Slime

Flash
When Green Slime enters the battlefield, counter target activated or triggered ability from an artifact or enchantment source. If a permanent's ability is countered this way, destroy that permanent.
Foretell {G} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Experiment Kraj

Experiment Kraj has all activated abilities of each other creature with a +1/+1 counter on it.
{T}: Put a +1/+1 counter on target creature.

Experimental Augury

Look at the top three cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Manaplasm

Whenever you cast a spell, Manaplasm gets +X/+X until end of turn, where X is that spell's mana value.

Bloom Hulk

When Bloom Hulk enters the battlefield, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Vinelasher Kudzu

Landfall — Whenever a land enters the battlefield under your control, put a +1/+1 counter on Vinelasher Kudzu.

Vannifar, Evolved Enigma

At the beginning of combat on your turn, choose one —
• Cloak a card from your hand. (Put it onto the battlefield face down as a 2/2 creature with ward {2}. Turn it face up any time for its mana cost if it's a creature card.)
• Put a +1/+1 counter on each colorless creature you control.

Printlifter Ooze

Deathtouch
Whenever Printlifter Ooze or another creature you control is turned face up, create a 0/0 green Ooze creature token with trample. The token enters the battlefield with X +1/+1 counters on it, where X is the number of other creatures you control.
Disguise {3}{G}

Vraska, Swarm's Eminence

Whenever a creature you control with deathtouch deals damage to a player or planeswalker, put a +1/+1 counter on that creature.
−2: Create a 1/1 black Assassin creature token with deathtouch and "Whenever this creature deals damage to a planeswalker, destroy that planeswalker."

Gluttonous Slime

Flash
Devour 1 (As this enters the battlefield, you may sacrifice any number of creatures. This creature enters the battlefield with that many +1/+1 counters on it.)

Oran-Rief Ooze

When Oran-Rief Ooze enters the battlefield, put a +1/+1 counter on target creature you control.
Whenever Oran-Rief Ooze attacks, put a +1/+1 counter on each attacking creature with a +1/+1 counter on it.

Contagion Engine

When Contagion Engine enters the battlefield, put a -1/-1 counter on each creature target player controls.
{4}, {T}: Proliferate twice. (Choose any number of permanents and/or players, then give each another counter of each kind already there. Then do it again.)

Prosthetic Injector

Equipped creature gets +0/+2 and has toxic 1. (Players dealt combat damage by equipped creature also get a poison counter.)
Equip {1}

Vraska, Scheming Gorgon

+2: Creatures you control get +1/+0 until end of turn.
−3: Destroy target creature.
−10: Until end of turn, creatures you control gain deathtouch and "Whenever this creature deals damage to an opponent, that player loses the game."

Radiant Fountain

When Radiant Fountain enters the battlefield, you gain 2 life.
{T}: Add {C}.

Scavenging Ooze

{G}: Exile target card from a graveyard. If it was a creature card, put a +1/+1 counter on Scavenging Ooze and you gain 1 life.

Serum Snare

Return target nonland permanent to its owner's hand. If that permanent had mana value 3 or less, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Prologue to Phyresis

Each opponent gets a poison counter.
Draw a card.

Splitting Slime

{4}{G}{G}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)
When Splitting Slime becomes monstrous, create a token that's a copy of Splitting Slime. (The token has no counters and isn't monstrous.)

Karn's Bastion

{T}: Add {C}.
{4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Aeve, Progenitor Ooze

Storm (When you cast this spell, copy it for each spell cast before it this turn. Copies become tokens.)
Aeve, Progenitor Ooze isn't legendary if it's a token.
Aeve enters the battlefield with a +1/+1 counter on it for each other Ooze you control.

Drown in Ichor

Target creature gets -4/-4 until end of turn. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Primordial Plasm

At the beginning of combat on your turn, another target creature gets +2/+2 and loses all abilities until end of turn.

Invasion of Muraganda

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When Invasion of Muraganda enters the battlefield, put a +1/+1 counter on target creature you control. Then that creature fights up to one target creature you don't control.

Invasion of Muraganda // Primordial Plasm

Corrosive Ooze

Whenever Corrosive Ooze blocks or becomes blocked by an equipped creature, destroy all Equipment attached to that creature at end of combat.

Experiment One

Evolve (Whenever a creature enters the battlefield under your control, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
Remove two +1/+1 counters from Experiment One: Regenerate Experiment One. (The next time this creature would be destroyed, instead tap it, remove it from combat, and heal all damage on it.)

Mephitic Ooze

Mephitic Ooze gets +1/+0 for each artifact you control.
Whenever Mephitic Ooze deals combat damage to a creature, destroy that creature. The creature can't be regenerated.

Everglades

Everglades enters the battlefield tapped.
When Everglades enters the battlefield, sacrifice it unless you return an untapped Swamp you control to its owner's hand.
{T}: Add {C}{B}.

Necrotic Ooze

As long as Necrotic Ooze is on the battlefield, it has all activated abilities of all creature cards in all graveyards.

The Mimeoplasm

As The Mimeoplasm enters the battlefield, you may exile two creature cards from graveyards. If you do, it enters the battlefield as a copy of one of those cards with a number of additional +1/+1 counters on it equal to the power of the other card.

Vine Trellis

Defender (This creature can't attack.)
{T}: Add {G}.

Ravenous Slime

Ravenous Slime can't be blocked by creatures with power 2 or less.
If a creature an opponent controls would die, instead exile it and put a number of +1/+1 counters equal to that creature's power on Ravenous Slime.

Virulent Wound

Put a -1/-1 counter on target creature. When that creature dies this turn, its controller gets a poison counter.

Prime Speaker Vannifar

{T}, Sacrifice another creature: Search your library for a creature card with mana value equal to 1 plus the sacrificed creature's mana value, put that card onto the battlefield, then shuffle. Activate only as a sorcery.

Acidic Slime

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
When Acidic Slime enters the battlefield, destroy target artifact, enchantment, or land.

Carrion Call

Create two 1/1 green Phyrexian Insect creature tokens with infect. (They deal damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Unnatural Restoration

Return target permanent card from your graveyard to your hand. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Bioplasm

Whenever Bioplasm attacks, exile the top card of your library. If it's a creature card, Bioplasm gets +X/+Y until end of turn, where X is the exiled creature card's power and Y is its toughness.

Voidslime

Counter target spell, activated ability, or triggered ability. (Mana abilities can't be targeted.)

Contagion Clasp

When Contagion Clasp enters the battlefield, put a -1/-1 counter on target creature.
{4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Mwonvuli Ooze

Cumulative upkeep {2} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay {2} for each age counter on it.)
Mwonvuli Ooze's power and toughness are each equal to 1 plus twice the number of age counters on it.

Wall of Roots

Defender
Put a -0/-1 counter on Wall of Roots: Add {G}. Activate only once each turn.

Tainted Observer

Flying
Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
Whenever another creature enters the battlefield under your control, you may pay {2}. If you do, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Swamp

Biowaste Blob

Oozes you control get +1/+1.
At the beginning of your upkeep, if you control a commander, create a token that's a copy of Biowaste Blob.

Uchuulon

Uchuulon's power is equal to the number of Crabs, Oozes, and/or Horrors you control.
Horrific Symbiosis — At the beginning of your end step, exile up to one target creature card from an opponent's graveyard. If you do, create a token that's a copy of Uchuulon.

Gelatinous Cube

Engulf — When Gelatinous Cube enters the battlefield, exile target non-Ooze creature an opponent controls until Gelatinous Cube leaves the battlefield.
Dissolve — {X}{B}: Put target creature card with mana value X exiled with Gelatinous Cube into its owner's graveyard.

Slogurk, the Overslime

Trample
Whenever a land card is put into your graveyard from anywhere, put a +1/+1 counter on Slogurk, the Overslime.
Remove three +1/+1 counters from Slogurk: Return it to its owner's hand.
When Slogurk leaves the battlefield, return up to three target land cards from your graveyard to your hand.

Gobbling Ooze

{G}, Sacrifice another creature: Put a +1/+1 counter on Gobbling Ooze.

Umori, the Collector

Companion — Each nonland card in your starting deck shares a card type. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
As Umori, the Collector enters the battlefield, choose a card type.
Spells you cast of the chosen type cost {1} less to cast.

Slime Against Humanity

Create a 0/0 green Ooze creature token with trample. Put X +1/+1 counters on it, where X is two plus the total number of cards you own in exile and in your graveyard that are Oozes or are named Slime Against Humanity.
A deck can have any number of cards named Slime Against Humanity.

Insidious Roots

Creature tokens you control have "{T}: Add one mana of any color."
Whenever one or more creature cards leave your graveyard, create a 0/1 green Plant creature token, then put a +1/+1 counter on each Plant you control.

Glistening Sphere

Glistening Sphere enters the battlefield tapped.
When Glistening Sphere enters the battlefield, proliferate.
{T}: Add one mana of any color.
Corrupted — {T}: Add three mana of any one color. Activate only if an opponent has three or more poison counters.

Inexorable Tide

Whenever you cast a spell, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Contentious Plan

Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Draw a card.

Smell Fear

Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Target creature you control fights up to one target creature you don't control.

Slurrk, All-Ingesting

Slurrk, All-Ingesting enters the battlefield with five +1/+1 counters on it.
Whenever Slurrk or another creature you control dies, if it had a +1/+1 counter on it, put a +1/+1 counter on each creature you control that has a +1/+1 counter on it.
Partner (You can have two commanders if both have partner.)

Ooze Flux

{1}{G}, Remove one or more +1/+1 counters from among creatures you control: Create an X/X green Ooze creature token, where X is the number of +1/+1 counters removed this way.

Ooze Garden

{1}{G}, Sacrifice a non-Ooze creature: Create an X/X green Ooze creature token, where X is the sacrificed creature's power. Activate only as a sorcery.

Steady Progress

Island

Ichormoon Gauntlet

Planeswalkers you control have "[0]: Proliferate" and "[−12]: Take an extra turn after this one."
Whenever you cast a noncreature spell, choose a counter on target permanent. Put an additional counter of that kind on that permanent.

Planewide Celebration

Choose four. You may choose the same mode more than once.
• Create a 2/2 Citizen creature token that's all colors.
• Return target permanent card from your graveyard to your hand.
• Proliferate.
• You gain 4 life.

Vat Emergence

Put target creature card from a graveyard onto the battlefield under your control. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Predator Ooze

Indestructible
Whenever Predator Ooze attacks, put a +1/+1 counter on it.
Whenever a creature dealt damage by Predator Ooze this turn dies, put a +1/+1 counter on Predator Ooze.

Inexorable Blob

Delirium — Whenever Inexorable Blob attacks, if there are four or more card types among cards in your graveyard, create a 3/3 green Ooze creature token that's tapped and attacking.

Consumptive Goo

{2}{B}{B}: Target creature gets -1/-1 until end of turn. Put a +1/+1 counter on Consumptive Goo.

Contaminant Grafter

Trample, toxic 1
Whenever one or more creatures you control deal combat damage to one or more players, proliferate.
Corrupted — At the beginning of your end step, if an opponent has three or more poison counters, draw a card, then you may put a land card from your hand onto the battlefield.

Mitotic Slime

When Mitotic Slime dies, create two 2/2 green Ooze creature tokens. They have "When this creature dies, create two 1/1 green Ooze creature tokens."

Fertile Thicket

Fertile Thicket enters the battlefield tapped.
When Fertile Thicket enters the battlefield, you may look at the top five cards of your library. If you do, reveal up to one basic land card from among them, then put that card on top of your library and the rest on the bottom in any order.
{T}: Add {G}.

Ancient Ooze

Ancient Ooze's power and toughness are each equal to the total mana value of other creatures you control.

Vraska, Golgari Queen

+2: You may sacrifice another permanent. If you do, you gain 1 life and draw a card.
−3: Destroy target nonland permanent with mana value 3 or less.
−9: You get an emblem with "Whenever a creature you control deals combat damage to a player, that player loses the game."

Wall of Vines

Defender (This creature can't attack.)
Reach (This creature can block creatures with flying.)

Wall of Blossoms

Defender
When Wall of Blossoms enters the battlefield, draw a card.

Creeping Tar Pit

Creeping Tar Pit enters the battlefield tapped.
{T}: Add {U} or {B}.
{1}{U}{B}: Creeping Tar Pit becomes a 3/2 blue and black Elemental creature until end of turn and can't be blocked this turn. It's still a land.

Consuming Blob

Consuming Blob's power is equal to the number of card types among cards in your graveyard and its toughness is equal to that number plus 1.
At the beginning of your end step, create a green Ooze creature token with "This creature's power is equal to the number of card types among cards in your graveyard and its toughness is equal to that number plus 1."

Portcullis Vine

Defender (This creature can't attack.)
{2}, {T}, Sacrifice a creature with defender: Draw a card.

Spread the Sickness

Destroy target creature, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Necroplasm

At the beginning of your upkeep, put a +1/+1 counter on Necroplasm.
At the beginning of your end step, destroy each creature with mana value equal to the number of +1/+1 counters on Necroplasm.
Dredge 2 (If you would draw a card, you may mill two cards instead. If you do, return this card from your graveyard to your hand.)

Flooded Grove

{T}: Add {C}.
{G/U}, {T}: Add {G}{G}, {G}{U}, or {U}{U}.

Vraska the Unseen

+1: Until your next turn, whenever a creature deals combat damage to Vraska the Unseen, destroy that creature.
−3: Destroy target nonland permanent.
−7: Create three 1/1 black Assassin creature tokens with "Whenever this creature deals combat damage to a player, that player loses the game."

Biogenic Ooze

When Biogenic Ooze enters the battlefield, create a 2/2 green Ooze creature token.
At the beginning of your end step, put a +1/+1 counter on each Ooze you control.
{1}{G}{G}{G}: Create a 2/2 green Ooze creature token.

Fuel for the Cause

Counter target spell, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Phytotitan

When Phytotitan dies, return it to the battlefield tapped under its owner's control at the beginning of their next upkeep.

Evolution Sage

Landfall — Whenever a land enters the battlefield under your control, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Forest

Ochre Jelly

Trample
Ochre Jelly enters the battlefield with X +1/+1 counters on it.
Split — When Ochre Jelly dies, if it had two or more +1/+1 counters on it, create a token that's a copy of it at the beginning of the next end step. The token enters the battlefield with half that many +1/+1 counters on it, rounded down.